Montreal bay & bow window installation with a window seat

A bay or bow projects out past the wall to add a window seat and pull daylight in from three sides. We size the structural support, insulate the head and seat board, flash the roof watertight and air-seal the box to the house — then finish it inside and out.

Every opening measured on-site

Full air-seal on every unit

Written frame + sealed-glass warranty

A bay window that adds a seat and light

A bay or bow window projects out from the wall to create a bright nook inside and standout curb appeal outside. A bay pairs a central picture window with two angled flankers; a bow curves four or more units for a softer, rounded shape. The flanking sashes are usually casement windows or double-hung windows, and either layout turns a flat wall into a window seat and a sunny reading corner.

Because the unit hangs past the wall, it lives in the weather on every side — which in Montreal means the head and seat board have to be insulated and the box air-sealed, or it becomes a cold, sagging spot. We engineer the support, insulate the projection and seal it to the house, and finish it with the same care as our energy-efficient replacement work — warm and solid, not just pretty on install day.

Four steps from free measure to sealed install

Book the estimate

Call, text or use the form. We book a free in-home visit — no obligation, no high-pressure sales table.

On-site measure

We measure every opening, check the frames and sills for rot or water damage, and walk through material, style and glass options in plain language.

Written quote

Line-item quote with the window line, glass package, U-factor, warranty and haul-away on one page. Financing attached when you want it.

Install, cleanly

Drop cloths, boot covers and a full air-seal on every unit. Old windows hauled away and a walkthrough of your new windows plus warranty registration.

Engineered support, insulated seat board

A bay or bow needs proper structural support — cabling or knee-bracing sized to the unit — plus full insulation of the roof, floor and sides of the projection to hold up through a a hard winter. We handle both, air-seal the assembly to the wall, and finish it inside and out. Prefer a single wide pane instead? A picture window is the airtight alternative.

The written quote spells out the configuration, the glass package, the support and the finish, so you know exactly what is included. Ask about pairing operable awning windows for airflow or an energy-efficient upgrade on nearby openings — every unit carries a written frame-and-glass warranty.

Montreal bay & bow window installation, answered

Cost, winter warmth and bay-versus-bow for projected windows.

How much does a bay window cost in Montreal?

A bay or bow window typically runs about $2,500–$5,000 installed in Montreal, depending on the size, the configuration, the glass package and how much structural support and finishing the projection needs. The flanking windows' style — casement versus double-hung — and triple-pane glass move the number, as does any interior seat or trim work. Because these are engineered, projecting units, we always measure and quote in writing rather than guess, and the quote spells out the window, the support, the insulation and the finish so there are no surprises.

Are bay windows cold in winter?

Not when it is installed correctly — and that is the whole game with a bay or bow. Because the unit projects out into the weather, the roof, floor and sides of the box have to be fully insulated and the whole assembly air-sealed to the wall, or you get a cold nook and condensation. We insulate and flash the projection properly and spec efficient triple-pane glass, so the bay stays as warm and comfortable as the rest of the room. Done right, it is a cozy spot even in the depths of winter, not a draft you avoid.

What is the difference between bay and bow?

A bay window has three sections — a larger central window flanked by two units set at an angle (usually 30 or 45 degrees) — giving a crisp, projecting shape. A bow window uses four or more equal units joined in a gentle arc, for a softer, rounded curve that projects less sharply. Bays make a bolder architectural statement and a deeper seat; bows suit a wider opening and a more traditional, flowing look. We help you pick the configuration that fits your wall, your room and the exterior of the house.

Can I add a window seat under a bay?

Yes — a bay creates a natural nook for a bench or window seat, and we build and insulate the projection to carry it solidly.

How long does a bay or bow installation take?

Usually a day for a standard unit, longer if structural support or interior finishing is involved; we give a realistic timeline in the written quote.

Book a free Montreal bay & bow window installation estimate

Book a free in-home measure and a written, itemized quote for bay or bow window installation anywhere across Montreal and the surrounding towns. Properly supported, fully insulated for our winters, and backed by a written frame-and-glass warranty — built by our own crews, no subcontractors, no pressure.

Locally owned · Insured · ENERGY STAR® · Free written estimates

Real Montreal reviews

What Montreal homeowners say after install day

★★★★★ 4.9 · 118 reviews on Google

★★★★★

The bay window created a bright reading nook we use every day. They engineered the support properly so it feels rock solid.

C. Marchildon

Homeowner, Montreal

Our bow window is stunning and, more importantly, warm — they insulated the projection so there is no cold nook in the depths of winter.

N. Bhattacharya

Homeowner, Laval

Adds so much light and curb appeal. The written quote covered the support and finish so there were no surprises.

K. Dubois

Homeowner, Longueuil

Beautiful bay, solid build, and a tidy job inside and out. Worth every penny.

T. Ali

Homeowner, Gatineau

Montreal bay & bow window installation with a window seat

A bay window that adds a seat and light

Four steps from free measure to sealed install

Book the estimate

On-site measure

Written quote

Install, cleanly

Engineered support, insulated seat board

More Montreal window styles we install

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Fiberglass Windows

Wood Windows

Aluminum Windows

Montreal bay & bow window installation, answered

What Montreal homeowners say after install day

Montreal window guides

How to Choose the Right Windows for Your Montreal Home

Book a free Montreal bay & bow window installation estimate